1. Field of the Invention
The present invention relates generally to attachments and fixtures for handheld power tools, and more particularly to a base for a router type power tool which provides support for the router while working atop a planar workpiece. The present tilt base has a flat, planar base plate with a router base attached thereto by means of a pair of opposed lateral pivots, allowing the router secured within the base to be adjustably tilted to angle the cutting bit and its resultant cut as desired.
2. Description of the Related Art
The router is a well known type of power tool, and is useful for cutting grooves, slots, mating joints, and other specialized shapes in wood, plastics, and other materials. There are numerous different variations on the handheld router, made by a number of different manufacturers. However, they all essentially comprise an electric (or perhaps pneumatic) motor in a case or housing, with the housing having a base extending from one end thereof. An output shaft or mandrel extends from the base end of the device, and provides for removable attachment of any one of a number of differently configured cutting bits thereon. Such a router is generally manipulated by hand over a workpiece to form the desired cut in the material, with accuracy provided by a guide fence, template, or other aid secured to the work table and/or workpiece.
The above general description of the configuration and use of a router is well known. However, such a relatively simple tool has its limitations. Perhaps the most obvious of these limitations is the fact that the rotational axis of the cutting bit is fixed concentrically relative to the housing and its base. This is fine for many, if not most, operations for which routers are used. However, the operator often wishes to position the cutting bit at an angle other than 90° to the surface of the workpiece. An example of such is when forming a beveled edge on a workpiece. There are a number of router and router table combination tools in which the router is essentially permanently installed beneath the table, with the cutting bit projecting through a hole in the table. Many such devices include various adjustments for the router position relative to the table surface, including tilt for the cutting axis of the tool. However, there are only a relatively few handheld routers which provide any means of holding the cutting axis of the tool at some predetermined angle other than normal to the plane of the base and the surface of the workpiece upon which the base is placed.
The present invention responds to this need by providing a tilt base for a handheld router which allows the angle of the output shaft and cutting blade attached thereto to be adjusted as desired from its standard orientation normal to the workpiece surface, to some other predetermined angle as desired. The present tilt base for a router may be constructed from an existing conventional router base, with the addition of a few components and a base plate upon which the components and router are assembled. The result is a relatively inexpensive tool and attachment which provide versatility only matched by considerably more costly and more cumbersome tools.
A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 2,630,151 issued on Mar. 3, 1953 to Roger F. Turnbull, titled “Portable Track-Guided Tilt Router,” describes an assembly in which the router base has a pivot shaft attached thereto by a pair of opposed, laterally offset bosses or lugs. The router housing or case has a lateral flange extending from the lower portion thereof with a pivot shaft attachment boss extending therefrom, through which the router base pivot shaft passes. The router may also be moved linearly along the pivot shaft, as well as being angularly positionable about the axis defined by the pivot shaft. However, the lateral offset of the router mandrel and its cutting bit from the pivot axis results in the cutting bit being raised above the plane of the work when other than normal to the work plane. It is also noted that while Turnbull provides an adjustable lower position stop for the angular movement of his router, he does not provide any means of locking the angle of the router relative to the base. This is because the Turnbull device is configured so the router may be quickly and easily pivoted upwardly from its working position to position the cutting bit precisely over a workpiece therebelow. The Turnbull router assembly does not appear to be designed for to cutting a workpiece at other than 90° to the surface of the workpiece, and the tool does not readily provide for such use.
U.S. Pat. No. 4,827,996 issued on May 9, 1989 to Lawrence M. Cotton et al., titled “Power Tool For Trimming Laminate,” describes a router and accessories comprising a number of interchangeable bases which may be secured to the router housing. One of the bases (FIGS. 22 through 24 of the Cotton et al. disclosure) provides for the adjustable tilt of the router when secured therein. While the tilt pivot axis is essentially concentric with the centerline of the router and its cutting axis, the tilt base is asymmetrical. This results in greater angular travel in one direction than in the other, for a router secured therein. In contrast, the present tilt base is symmetrical to each side of the lateral tilt axis, permitting equal arcuate travel in each direction.
U.S. Pat. No. 4,919,176 issued on Apr. 24, 1990 to Benton W. Gachet et al., titled “Ramped device for Finite Positioning Of Panel Joint Forming Tool,” describes a router assembly with a base plate having an asymmetrical thickness. This allows the router to cut identically shaped cuts simultaneously in two workpieces staggered in height, thereby allowing the two cuts to mate or mesh with one another when the two workpieces are assembled with their surfaces coplanar with one another. The router base has a tapered base plate surface, with the relative height of one of the workpieces being adjusted by means of a shim having the same angular taper as the base taper angle. However, Gachet et al. do not provide any means of adjusting the angle of the router itself, or of its rotary shaft and cutting bit relative to the base of their device.
U.S. Pat. No. 5,396,937 issued on Mar. 14, 1995 to Allen H. Clausen, titled “Router Table,” describes a tilt table for a router which is essentially permanently installed to its base, which is in turn installed beneath the table. The assembly is not portable, as is the present invention. The Clausen router cannot be angularly adjusted relative to its base or to the portion of the overlying table to which it is immovably affixed. The angular adjustment of the Clausen router and table is provided between the leaf or portion of the overlying table to which his router base is attached and the adjacent fixed table structure, not between the router housing and its base plate, as in the present invention.
U.S. Pat. No. 5,611,378 issued on Mar. 18, 1997 to Kenneth M. Brazell, titled “Tilting Router Table,” describes another router and table combination in which the router is essentially permanently installed beneath the table with the cutting bit projecting upwardly through. a hole in the table. One side of the table can be tilted normal to the router attachment side to form a fence, if so desired. Also, the entire table and attached router can be tilted 90° to its standard position if desired, with the fence portion horizontal and the opposite table surface portion, with attached router, in a vertical plane. However, none of the adjustments of the Brazell router table permit the router to be tilted at some angle other than 90° to either or both portions of the tabletop, nor does Brazell disclose any provision for a tilt base for a handheld router, as provided by the present invention.
U.S. Pat. No. 5,725,038 issued on Mar. 10, 1998 to Edwin C. Tucker et al., titled “Router Baseplate And Table,” describes an assembly which facilitates installation of a router beneath a router table. The router has a plate immovably affixed to the base end of the housing thereof, with the table having an opening therein which substantially matches the router plate. The table opening includes an inwardly projecting flange therearound and below the upper edge thereof, upon which the router plate rests when the plate is placed in the table opening. The flange of the table opening includes a pair of opposed slots therein, through which the edge of the router plate may be guided from below to position the plate above the table while the router remains below the table and attached to the plate. However, once the router and its plate have been installed in the table, the router cannot be tilted relative to the table surface. The Tucker router and table assembly does nothing more than provide for rapid and easy installation and removal of the router and its affixed plate to and from the table. Once the router has been placed in the table, it cannot be tilted or positionally adjusted in any way.
U.S. Pat. No. 5,772,368 issued on Jun. 30, 1998 to Ransom D. Posh, titled “Full-Size Router Tilt Base,” describes several embodiments of a handheld router and tilt base assembly. The assembly includes a router mounting collar which is pivotally secured to opposed upstanding lugs or ears which extend from a base plate. However, the Posh assembly differs considerably from the present assembly, in that Posh includes a pair of downwardly extending tilt stop rods attached to the mounting collar. These stop rods extend below the plane of the base plate, and limit use of the Posh router assembly only to edge work. Any attempt to use the Posh router assembly to rout out an angled slot or groove in the central area of a panel or the like, would result in the two angle stop rods interfering with the workpiece panel. Posh also complicates his assembly further by providing a slot and locking knob above the pivot point on each of the upstanding lugs extending from the base plate. Since Posh describes these devices as serving to set and/or limit the angular adjustment of his router assembly, the tilt stop rods appear to be a duplication. In contrast, the present router tilt base is devoid of componentry extending below the base plate, other than the router bit itself. Moreover, the tilt attachment means of the present assembly is considerably more elegant than that of the Posh assembly, requiring only a single bolt on each side. The provision of handles and other features on the router housing base also serves to eliminate complexities in the base structure, where Posh provides attachment holes for handles and other componentry. It is also noted that the Posh router mounting collar or base lacks any form of relatively wide skirt, for greater stability. While the router base of the present invention also lacks such a wide skirt in order to provide the required tilt clearance, the opposite base plate attachment lugs are spaced somewhat more widely than the diameter of the major portion of the router base. This greatly facilitates access to the router cutting bit when changing bits, a better view of the routing operation while underway, and other benefits not provided by the narrow width of the Posh assembly between its opposed pivots.
U.S. Pat. No. 6,138,372 issued on Oct. 31, 2000 to Roger R. Newman, titled “Router Guide Apparatus,” describes a relatively complex assembly having a “reference member” or base plate which is pivotally connected to the body component, to which the router is secured. The body component secures to the base plate generally along the centerline of the body component, which results in half of the body component extending below the plane of the workpiece when the body component and router are tilted relative to the base plate. The Newman assembly thus has the same limitations as the tilt assembly of the Posh '368 U.S. patent discussed immediately above, in that the Newman device can only be used along a workpiece edge and cannot be used to rout an angled slot or the like in the general center of the workpiece.
U.S. Pat. No. 6,223,794 issued on May 1, 2001 to James Jones, titled “Woodworking Station,” describes an assembly in which the router is secured in a stand resembling a drill press. The rotational axis of the router cutting bit is fixed in the stand. The router can translate linearly upwardly and downwardly in the stand, but cannot be tilted relative to the stand. The only means of angularly adjusting the router relative to the workpiece is by adjusting the tilt of the underlying table beneath the router. The Jones router cannot be held and manipulated by hand when attached to its mounting, as can the present router and tilt assembly.
British Patent Publication No. 2,375,075 published on Nov. 6, 2002 to Denis Whitaker, titled “A Router Tiltably Mounted On A Base,” describes a router having an integral mounting housing, with the router permanently installed therein. The mount extends above a pair of parallel columns which provide for linear height adjustment of the router and its cutting bit relative to the underlying workpiece. The bases of the columns, in turn, attach to a pair of pivots which extend upwardly from the base plate, which is placed atop the workpiece. The base plate is asymmetrical, having an offset angular tilt stop to one side of one of the column pivots. The tilt stop of the Whitaker router assembly limits the assembly to tilting in only one direction. The Whitaker device cannot be tilted equally to either side of vertical, as can the present router and tilt base assembly. Moreover, the base plate of the Whitaker router assembly is relatively small for the height of the router, and does not have the elongate configuration, and corresponding stability, of the base plate of the present router and tilt base assembly.
Finally, a printout from the World Wide Web website for the Porter Cable Company includes a web page published at least on Sep. 26, 2003, titled “po690”, which describes a Porter-Cable model PO-690 router motor, housing, and base assembly. The present invention makes a modification of the base portion of the above assembly by removing most of the larger diameter skirt area at the output end of the base, thereby providing a tilt clearance area to each side of the device. The portions of the depending skirt of the base immediately below each of the handles are left in place and serve as pivot ears or lugs for attaching the modified device to a base plate, which is placed atop the workpiece during operation. Porter-Cable does not provide such a modification to any of its router tools, nor does it provide any of the additional componentry of the present invention which is required for the tilt operation of the modified router base. It should be noted that the modification to a conventional router base taught by the present invention may be made to the handheld router base of many different models of routers made by different manufacturers. However, the present inventor is not aware of any other manufacturers who provide such a modification to any of their router products.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus a tilt base for a router tool solving the aforementioned problems is desired.